BoilerFaultCodesWhat the manual says
Manufacturer manualFlow sensor temperature rise incorrect. The time taken for the flow temperature to rise is too great.
What causes this fault?
This fault occurs when the boiler's internal sensors detect that the water isn't heating up at the expected speed after the burner ignites. The most common reason is a restriction in water flow caused by a failing pump or a buildup of debris, preventing heat from being moved away from the heat exchanger efficiently.
This issue often surfaces in autumn when the heating is turned back on after a summer of inactivity, which can cause the internal pump to seize or stick.
Engineer required
This is a high severity fault. Stop using the boiler and call a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
Avoid the next call-out bill
A cover plan would handle faults like 0A16: no call-out fees, no surprise bills.
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